1. Field of the Invention
This invention relates to a strip continuous supply apparatus and method preferred for application to a feeding apparatus or the like of a rotary press.
2. Description of the Related Art
In a machine, for example, a rotary press, that uses a roll (a web in wound form) while unwinding it, an operation is continued by automatically splicing a roll being unwound (i.e., an old web roll) to a new roll (a new web roll) by use of an automatic splicing apparatus, without stopping the operation of the machine, when the old web roll approaches the end of its unwinding (see Japanese Patent Application Laid-Open No. 2002-308485).
Conventionally, a diameter measuring device for a new web roll in an automatic splicing apparatus of an offset rotary press has been provided with a rotary, encoder for measuring the angle of rotation of a support shaft of a turret arm, the rotary encoder being provided on the support shaft of the turret arm. The diameter measuring device also has a transmission type photosensor provided in a direction intersecting a transport path of the new web roll transported by the turret arm. Because of this arrangement, the angle of rotation of the turret arm, from a reference position to a position where the photosensor detects the outside diameter of the new web roll, is detected. Based on this angle of rotation, the diameter of the new web roll is determined.
A splicing standby position setting device for the new web roll in the automatic splicing apparatus of the offset rotary press also has a similar transmission type photosensor provided in a direction intersecting the transport path of the new web roll transported by the turret arm. When the photosensor has detected the outside diameter of the new web roll, the rotation of the turret arm is stopped, and the new web roll is set at a splicing standby position.
With the above-described diameter measuring device and the splicing standby position setting device, however, if the outside diameter of the new web roll is smaller than the external dimension of the turret arm, the transmission type photosensor detects the turret arm earlier than the outside diameter of the new web roll, stopping the rotation of the turret arm. Thus, there are problems that the diameter of the new web roll cannot be determined accurately, and the new web roll cannot be set precisely at the splicing standby position.